Alex Behm has posted comments on this change. ( http://gerrit.cloudera.org:8080/8085 )
Change subject: IMPALA-5307: part 1: don't transfer disk I/O buffers out of parquet ...................................................................... Patch Set 6: (1 comment) http://gerrit.cloudera.org:8080/#/c/8085/6//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/8085/6//COMMIT_MSG@44 PS6, Line 44: There is a significant regression (50% increase in runtime) in > I'm pretty sure it's the memory copying - making a memory allocation should Makes sense. Might still be worth doing a quick experiment with MT_DOP to see if the regression remains the same (MT_DOP is easier to reason about). I'm definitely in favor of this change, but uncompressed Parquet with a lot of string columns is unfortunately very common, despite our recommendations. -- To view, visit http://gerrit.cloudera.org:8080/8085 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I767c1e2dabde7d5bd7a4d5c1ec6d14801b8260d2 Gerrit-Change-Number: 8085 Gerrit-PatchSet: 6 Gerrit-Owner: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com> Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Lars Volker <l...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Comment-Date: Wed, 27 Sep 2017 16:25:26 +0000 Gerrit-HasComments: Yes
